I don't know where this taco proposal actually comes from, but you have to wonder if she actually was into the idea or was turned off by the idea of a romantic gesture based on something available at Taco Bell.

Well I admit he's got me beat.I proposed at the hot dog cart in front of the hardware store.Dosen't take much to bring back memories of what happened to that foot long.Needless to say,my dreams of cheap nostalgic anniversary dinners has now been reserved for one brain cell only,shared equally with my last memory of what she so pleasantly looked like before I asked for her hand and one with mustard & onions.

I don't think it's a proposal, but a tie-in to "Inu x Boku SS" anime series, where that scene (main male character kneeling and holding main female character's hand) happens a number of times. Still, pretty cool, tortilla printing...